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Climate Proxy
In the study of past climates ("paleoclimatology"), climate proxies are preserved physical characteristics of the past that stand in for direct meteorological measurements and enable scientists to reconstruct the climatic conditions over a longer fraction of the Earth's history. Reliable global records of climate only began in the 1880s, and proxies provide the only means for scientists to determine climatic patterns before record-keeping began. A large number of climate proxies have been studied from a variety of geologic contexts. Examples of proxies include stable isotope measurements from ice cores, growth rates in tree rings, species composition of sub-fossil pollen in lake sediment or foraminifera in ocean sediments, temperature profiles of boreholes, and stable isotopes and mineralogy of corals and carbonate speleothems. In each case, the proxy indicator has been influenced by a particular seasonal climate parameter (e.g., summer temperature or monsoon intensity) at the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temperature Reconstruction Last Two Millennia
Temperature is a physical quantity that quantitatively expresses the attribute of hotness or coldness. Temperature is measured with a thermometer. It reflects the average kinetic energy of the vibrating and colliding atoms making up a substance. Thermometers are calibrated in various temperature scales that historically have relied on various reference points and thermometric substances for definition. The most common scales are the Celsius scale with the unit symbol °C (formerly called ''centigrade''), the Fahrenheit scale (°F), and the Kelvin scale (K), with the third being used predominantly for scientific purposes. The kelvin is one of the seven base units in the International System of Units (SI). Absolute zero, i.e., zero kelvin or −273.15 °C, is the lowest point in the thermodynamic temperature scale. Experimentally, it can be approached very closely but not actually reached, as recognized in the third law of thermodynamics. It would be impossible to extract ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Sheets
In glaciology, an ice sheet, also known as a continental glacier, is a mass of glacial ice that covers surrounding terrain and is greater than . The only current ice sheets are the Antarctic ice sheet and the Greenland ice sheet. Ice sheets are bigger than ice shelves or alpine glaciers. Masses of ice covering less than 50,000 km2 are termed an ice cap. An ice cap will typically feed a series of glaciers around its periphery. Although the surface is cold, the base of an ice sheet is generally warmer due to geothermal heat. In places, melting occurs and the melt-water lubricates the ice sheet so that it flows more rapidly. This process produces fast-flowing channels in the ice sheet — these are ice streams. Even stable ice sheets are continually in motion as the ice gradually flows outward from the central plateau, which is the tallest point of the ice sheet, and towards the margins. The ice sheet slope is low around the plateau but increases steeply at the ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vostok DeltaD DeltaO18
Vostok () refers to east in Russian but may also refer to: Spaceflight * Vostok programme, Soviet human spaceflight project * Vostok (spacecraft), a type of spacecraft built by the Soviet Union * Vostok (rocket family), family of rockets derived from the Soviet R-7 Semyorka ICBM designed for the human spaceflight programme * Vostok (crater), a crater explored by the Mars rover Opportunity * Vostok 1, the first human spaceflight Places * Vostok Island, located in the south of Kiribati's Line Islands * Uschod (Minsk Metro) (Russian name ''Vostok''), a station of Minsk Metro, Minsk, Belarus * Vostok Rupes, a mountain chain on planet Mercury Antarctica * Cape Vostok, the west extremity of the Havre Mountains and the northwest extremity of Alexander Island * Vostok Station, Russian (originally Soviet) Antarctic research station * Lake Vostok, a subglacial lake located beneath Vostok Station * Vostok Subglacial Highlands, an east extension of Gamburtsev Subglacial Mountains Russi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drilling
Drilling is a cutting process where a drill bit is spun to cut a hole of circular cross section (geometry), cross-section in solid materials. The drill bit is usually a rotary Cutting tool (machining), cutting tool, often multi-point. The bit is Pressure, pressed against the work-piece and rotated at rates from hundreds to thousands of revolutions per minute. This forces the cutting edge against the work-piece, cutting off Swarf, chips (swarf) from the hole as it is drilled. In Rock (geology), rock drilling, the hole is usually not made through a circular cutting motion, though the bit is usually rotated. Instead, the hole is usually made by hammering a drill bit into the hole with quickly repeated short movements. The hammering action can be performed from outside the hole (top-hammer drill) or within the hole (down-the-hole drill, DTH). Drills used for horizontal drilling are called drifter drills. In rare cases, specially-shaped bits are used to cut holes of non-circular cro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diameter
In geometry, a diameter of a circle is any straight line segment that passes through the centre of the circle and whose endpoints lie on the circle. It can also be defined as the longest Chord (geometry), chord of the circle. Both definitions are also valid for the diameter of a sphere. In more modern usage, the length d of a diameter is also called the diameter. In this sense one speaks of diameter rather than diameter (which refers to the line segment itself), because all diameters of a circle or sphere have the same length, this being twice the radius r. :d = 2r \qquad\text\qquad r = \frac. The word "diameter" is derived from (), "diameter of a circle", from (), "across, through" and (), "measure". It is often abbreviated \text, \text, d, or \varnothing. Constructions With straightedge and compass, a diameter of a given circle can be constructed as the perpendicular bisector of an arbitrary chord. Drawing two diameters in this way can be used to locate the center of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Core Sample
A core sample is a cylindrical section of (usually) a naturally-occurring substance. Most core samples are obtained by drilling with special drills into the substance, such as sediment or rock, with a hollow steel tube, called a core drill. The hole made for the core sample is called the "core hole". A variety of core samplers exist to sample different media under different conditions; there is continuing development in the technology. In the coring process, the sample is pushed more or less intact into the tube. Removed from the tube in the laboratory, it is inspected and analyzed by different techniques and equipment depending on the type of data desired. Core samples can be taken to test the properties of manmade materials, such as concrete, ceramics, some metals and alloys, especially the softer ones. Core samples can also be taken of living things, including human beings, especially of a person's bones for microscopic examination to help diagnose diseases. Methods The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Sheet
In glaciology, an ice sheet, also known as a continental glacier, is a mass of glacier, glacial ice that covers surrounding terrain and is greater than . The only current ice sheets are the Antarctic ice sheet and the Greenland ice sheet. Ice sheets are bigger than ice shelf, ice shelves or alpine glaciers. Masses of ice covering less than 50,000 km2 are termed an ice cap. An ice cap will typically feed a series of glaciers around its periphery. Although the surface is cold, the base of an ice sheet is generally warmer due to Geothermal activity, geothermal heat. In places, melting occurs and the melt-water lubricates the ice sheet so that it flows more rapidly. This process produces fast-flowing channels in the ice sheet — these are ice streams. Even stable ice sheets are continually in motion as the ice gradually flows outward from the central plateau, which is the tallest point of the ice sheet, and towards the margins. The ice sheet slope is low around the plate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. Antarctica is the fifth-largest continent, being about 40% larger than Europe, and has an area of . Most of Antarctica is covered by the Antarctic ice sheet, with an average thickness of . Antarctica is, on average, the coldest, driest, and windiest of the continents, and it has the highest average elevation. It is mainly a polar desert, with annual Climate of Antarctica#Precipitation, precipitation of over along the coast and far less inland. About 70% of the world's freshwater reserves are frozen in Antarctica, which, if melted, would raise global sea levels by almost . Antarctica holds the record for the Lowest temperature recorded on Earth, lowest measured temperature on Earth, . The coastal regions can reach temperatures over in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Byrd Station
The Byrd Station is a former research station established by the United States during the International Geophysical Year by U.S. Navy Seabees during Operation Deep Freeze II in West Antarctica. It was a year-round base until 1972, and then seasonal up to 2005. The station was built in 1957, and is located on the West Antarctic ice cap. It was accessible by overland ice traverse or by ski-equipped C-130 aircraft. History A joint Army, Navy, Air Force, and Marines operation supported an overland tractor train traverse that left out of Little America V in late 1956 to establish the station. The train was led by Army Major Merle Dawson and completed a traverse of over unexplored country in Marie Byrd Land to blaze a trail to a spot selected beforehand. The station consisted of a set of four prefabricated buildings and was erected in less than one month by U.S. Navy Seabees. It was commissioned on January 1, 1957. The original station ("Old Byrd") lasted about four years befo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Camp Century
Camp Century is an abandoned Arctic United States military scientific research base in Greenland, situated east-northeast of Pituffik Space Base. When built, Camp Century was publicized as a demonstration for affordable ice-cap military outposts and a base for scientific research. According to documents declassified in 1996, Camp Century was a preliminary camp for Project Iceworm, whose goal was to install a vast network of nuclear missile launch sites that could survive a first strike. Missiles were never fielded at the facility and obtaining the necessary consent from the Danish Government to do so was never broached. The camp operated from 1959 until 1967. It consisted of 21 tunnels with a total length of and was powered by a nuclear reactor. Project Iceworm was aborted after realization that the ice sheet was not as stable as originally assessed, and that the missile basing concept would not be feasible. The reactor was removed and Camp Century later was abandoned. Howev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cold Regions Research And Engineering Laboratory
The Cold Regions Research and Engineering Laboratory (CRREL) is a United States Army Corps of Engineers, Engineer Research and Development Center research facility headquartered in Hanover, New Hampshire, that provides scientific and engineering support to the U.S. government and its military with a core emphasis on cold environments. CRREL also provides technical support to non-government customers. CRREL arose from a consolidation of three antecedent organizations whose purpose was to understand frozen ground, permafrost, snow and ice as factors which were important in strategic northern areas during the Cold War. In its first 25 years CRREL researchers contributed to the understanding of polar ice caps, permafrost, and the engineering technology for developing natural resources in cold climates, such as Alaska. More recently, CRREL researchers have made contributions to science in climate change, the understanding of wave propagation for sensor systems, the control of snow on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Geophysical Year
The International Geophysical Year (IGY; ), also referred to as the third International Polar Year, was an international scientific project that lasted from 1 July 1957 to 31 December 1958. It marked the end of a long period during the Cold War when scientific interchange between East and West had been seriously interrupted. Sixty-seven countries participated in IGY projects, although one notable exception was the mainland China, People's Republic of China, which was protesting against the participation of the Republic of China (Taiwan). East and West agreed to nominate the Belgian Marcel Nicolet as secretary general of the associated international organization. The IGY encompassed fourteen Earth science disciplines: Auroral light, aurora, airglow, cosmic rays, Earth's magnetic field, geomagnetism, gravity, ionosphere, ionospheric physics, longitude and latitude determinations (precision mapping), meteorology, oceanography, Ionizing radiation, nuclear radiation, glaciology, seismo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
